在wkwebview中启用摄像头和麦克风访问

Question

我有一个针对移动设备进行了优化的Web应用程序，可用于getUserMedia访问网络摄像头和麦克风资源。

我WKWebView要将这个应用包装为A，因为我想提供本机应用体验。我知道，iOS不允许通过浏览器访问摄像机-
但有什么办法来获得权限的网络摄像头/麦克风与本机代码（沿着封装）和饲料这对Web应用程序-也许在某种程度上指向getUserMedia一个本地流源？

Answer 1

是的，看看cordova-plugin-iosrtc和cordova-plugin-wkwebview-
engine
。插件背后的想法如下：

1. 创建一个定义各种WebRTC类和函数的JavaScript文件（WebRTC.js），并将调用传递给WKWebView，例如：

(function() {
  if (!window.navigator) window.navigator = {};
  window.navigator.getUserMedia = function() {
    webkit.messageHandlers.callbackHandler.postMessage(arguments);
  }
})();

2. 在WKWebView中，在文档开始处插入脚本：

let contentController = WKUserContentController();
contentController.add(self, name: "callbackHandler")

let script = try! String(contentsOf: Bundle.main.url(forResource: "WebRTC", withExtension: "js")!, encoding: String.Encoding.utf8)
contentController.addUserScript(WKUserScript(source: script, injectionTime: WKUserScriptInjectionTime.atDocumentStart, forMainFrameOnly: true))

let config = WKWebViewConfiguration()
config.userContentController = contentController

webView = WKWebView(frame: CGRect.zero, configuration: config)

3. 收听从JavaScript发送的消息：

class ViewController: UIViewController, WKUIDelegate, WKNavigationDelegate, WKScriptMessageHandler {
  var webView: WKWebView!

  func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
    if message.name == "callbackHandler" {
      print(message.body)
      // make native calls to the WebRTC framework here
    }
  }
}

4. 如果需要在JavaScript领域中执行成功或失败回调，请直接在WKWebView中评估函数调用：

webView.evaluateJavaScript("callback({id: \(id), status: 'success', args: ...})", completionHandler: nil)

这些回调需要 在 调用 之前
存储在JavaScript中的哈希中postMessage，然后必须将哈希键发送到WKWebView。这是commandId插件中的。

int exec_id = 0;
function exec(success, failure, ...) {
  // store the callbacks for later
  if (typeof success == 'function' || typeof failure == 'function') {
    exec_id++;
    exec_callbacks[exec_id] = { success: success, failure: failure };
    var commandId = exec_id;
  }
  webkit.messageHandlers.callbackHandler.postMessage({id: commandId, args: ...})
}

// the native code calls this directly with the same commandId, so the callbacks can be performed and released
function callback(opts) {
  if (opts.status == "success") {
    if (typeof exec_callbacks[opts.id].success == 'function') exec_callbacks[opts.id].success(opts.args);
  } else {
    if (typeof exec_callbacks[opts.id].failure == 'function') exec_callbacks[opts.id].failure(opts.args);
  }
  // some WebRTC functions invoke the callbacks multiple times
  // the native Cordova plugin uses setKeepCallbackAs(true)
  if (!opts.keepalive) delete exec_callbacks[opts.id];
}

5.
当然，为您的项目添加NSCameraUsageDescription和NSMicrophoneUsageDescription权限Info.phtml" target="_blank">list。

Keep in mind this is a non-trivial task, but that’s the general idea behind
bridging JavaScript, WKWebView, and native framework code with asynchronous
callbacks.